Hi Donny,
you get algae because of incorrect FC to CYA ratio/ levels.
I suspect if you test your water with a reliable test kit, your CYA will be at such a level, that your FC level of 5 is insufficient to control the algae.
Your skimmer flap being stuck may be hindering the skimming, but is not the cause of the algae. If your circulation was that poor, your pump would be sucking air and cavitating.
If you dont have one, a reliable test kit is available at
www.tftestkits.net Most folks here will recommend the TF-100 with the XL option.
Once you know what your water is by testing, you will need to know what to do from there. If you follow these instructions, you will clear the pool of algae. Its a process though, not a none time shot, so dont expect a magic fix, it's not. It took a while for your pool to grow algae and will take a while to get rid of it.
SLAM the pool is the answer.
http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl
You will need to use Pool Math in order to determine how much chlorine to add to get to slam level. Use Pool Math to do that.
http://www.troublefreepool.com/calc.html
Your FC level required to kill the algae is the Shock level ... see the chart in teh link. In order to know your shock FC level though, you need to know the CYA,
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock